I’m Scaling a Bestseller From 100 to 1,000 Candles a Month — Should I Lock a Maximum Batch Size to Preserve Production Consistency?

Why a bestseller needs a batch-size cap

At 100 candles a month, a bestseller is usually made in one or two batches, often by the owner, and it comes out the same because the conditions barely change. At 1,000 a month, the pressure is to make bigger batches: more wax per melt, more oil per addition, a longer pour. Each of those shifts the conditions the formula was approved under.

The recipe does not change when the batch grows, but the candle can. A deeper tank holds heat longer, so oil may go in hotter. Oil has further to travel when stirred by hand. A longer pour means the last candles meet cooler wax after more time at heat. For an oil like Roasted Coffee, whose page says its vanillin causes slight yellowing in white wax, a longer time at heat can also make colour differences between batches easier to see.

So locking a maximum batch size is not bureaucracy. It holds constant the part of the process that percentages cannot describe. Think of it as a line in the formula: CSI 464, Roasted Coffee at 8%, 200 g jar, batch between X and Y kg.

Setting the cap and the working range

The maximum is simply the largest batch you have validated: poured with a same-day 1 kg control, sampled from the beginning, middle and end, cured and passed. If your largest proven batch is 10 kg, the cap is 10 kg, even if your melter could hold more.

Set a minimum as well. A very small batch in a large melter sits as a shallow pool that heats and cools differently from a full fill. If your validated batch filled the tank to a certain depth, running a third of that depth is a different process. A working range — say, from the smallest to the largest validated fill — is more honest than a single ceiling.

Weigh what the melter really holds before you write the range down. The CSI melter page states 9.5 litres per melt; at roughly 0.9 g per ml of melted soy wax that is about 8.5 kg, although the variant is sold as the 10 kg capacity. Your cap must be a weighed figure, not a label.

The volume arithmetic at a fixed cap

Here is what growth looks like when the batch size stays fixed. The formula is CSI 464 with Roasted Coffee at 8% of total weight in 200 g jars.

Add the planning allowance to the monthly total. With 5% wastage, 1,000 good candles need about 1,000 ÷ 0.95 = 1,053 candle-equivalents, which is roughly 210.5 kg of scented wax: nine 25 kg batches, with the last one short, or a planned top-up batch inside your validated range.

That last point is the real trade-off. Eight batches a month means eight rounds of set-up, cleaning and records instead of four at 50 kg. Measure your own set-up and clean-down time for one batch, multiply it out, and decide whether the extra hours justify validating a larger size. Often they do not, at least until volume grows again.

Raising the cap: change control for a bestseller

There will be a point where a larger batch makes sense. Handle it as a formal change, not a gradual drift.

Whatever size you run, add oil below its published flashpoint — about 191–193°C for Roasted Coffee — and never with the melter at its maximum setting. Larger batches mean more hot wax moving around the room, so plan clear routes between melter and pouring bench.

When a batch has already gone over the cap

It happens: a rush week, an extra carton opened, and a 35 kg batch of the bestseller has been poured where the cap was 25 kg. Treat that batch as unvalidated, not as bad. The candles may be perfectly good; you simply have no evidence yet.

First, contain it. Keep the over-cap candles on a separate shelf with a clear label, apart from stock made within the range, and do not mix them into orders. If jars were numbered in pour order, pull candles from the first, middle and last parts of the pour; if they were not, pull from the first and last trays filled, which is the next best record of sequence.

Second, compare. Burn those candles beside a retained candle from a normal 25 kg batch of the same month, at a matching cure age, and beside a fresh 1 kg control if the same wax and oil lots are still available. Look especially at the last-poured candles, where extra hold time and cooler wax would show first, and at colour, since Roasted Coffee's vanillin base can make warmer tones more visible after longer heat.

Third, decide. If every position matches, release the batch and note the deviation on its sheet. If the late candles differ, sell only the positions that passed, and keep the rest back for use as testers or a lower-grade line, rather than letting them reach regular customers. Either way, record why the cap was exceeded and change the routine that allowed it.

Keeping eight batches a month identical

A cap controls size. Consistency across many batches also needs the other conditions held steady. Use one batch sheet for every batch of the bestseller, with the same fields each time: wax and oil lot, weighed quantities, wax temperature at oil addition read on a separate thermometer — the melter display carries a stated ±10°C deviation — mixing time, time from oil addition to first and last jar, and candle count.

Keep one retained candle from each batch, labelled with batch and position, and compare a new batch's retain against the previous month's every so often. When a new lot of wax or oil arrives, pour a small control from it before it enters bestseller production.

Supervise every comparison burn from start to finish, and put out any candle that begins to smoke or flare. And when you buy for this rhythm, remember that wax quantities above the 10 kg pack are quoted on WhatsApp; a steady monthly volume at a fixed batch size makes that conversation far easier to plan.

Where this page fits

CSI already has guides that cover parts of this question. This page covers the failure investigation for the question above; these go deeper on the rest:

Three things to buy for this job

Frequently asked questions